redirecting my user to different page fails with error

i have activated wp block admin and modified line no 21 to redirect my user to home page bt when i cross checkked it by creating a member and when i type wp-admin in the url it redirect me on error page saying u dont have enough permission to view this page..in mozilla bt strange on ie and crome when i login frm chrome and ie they both takes the member to wp-admin and the same error msg appear saying u dont have enough permission ? how to fix this